oscillator piston forward and backward resulting in an air volume (tidal volume) displacement. The effect of the amplitude on the ΔP that it is changed by the displacement of the oscillator piston and hence the oscillatory pressure (ΔP). The power setting interacts with PAW conditions existing within the patient circuit to produce the resulting ΔP. % Inspiratory time The percent of inspiratory time is a setting which determines the percent of cycle time the piston is traveling toward (or at its final inspiratory position). The inspiratory percent range is 30—50%. Frequency The frequency setting is measured in hertz (hz). The control knob is a 10-turn clockwise-increasing potentiometer covering a range of 3 Hz to 15 Hz. The set frequency is displayed on a digital meter on the face of the ventilator. One Hertz is (-/+5%) equal to 1 breath per second, or 60 breaths per minute (e.g., 10 Hz = 600 breaths per minute). Changes in frequency are inversely proportional to the amplitude and thus delivered tidal volume. Breaths per minute (f) Oscillation trough pressure Oscillation trough pressure is the instantaneous pressure within the HFOV circuit following the oscillating piston reaching its complete negative deflection. Transtracheal jet ventilation Transtracheal jet ventilation refers to a type of high-frequency ventilation, low tidal volume ventilation provided via a laryngeal catheter by specialized ventilators that are usually only available in the operating room or intensive care unit. This procedure is occasionally employed in the operating room when a difficult airway is anticipated. Such as Treacher Collins syndrome, Robin sequence, head and neck surgery with supraglottic or glottic obstruction). Adverse effects The adverse side effects noted during the use of high-frequency ventilation include those commonly found during the use of conventional positive pressure ventilators. These adverse effects include: Pneumothorax Pneumopericardium Pneumoperitoneum Pneumomediastinum Pulmonary interstitial emphysema Intraventricular hemorrhage Necrotizing tracheobronchitis Bronchopulmonary dysplasia See also Mechanical ventilation Respiratory therapy Ventilator associated lung injury References Modes of mechanical ventilation Pulmonology Respiratory therapy